grass in cement pavement seams

Hello, I want to clean out and seal the seams (and also some cracks) in the cement pavement and driveway around the house -- please see the photo. These seams are 1/4" - 1/2" wide, up to 1" deep, are packed with dirt and retain enough moisture to work as mini-planter boxes.

Was wondering about the right product for long-term sealing the seams that are this wide and deep, so that it doesn't crack due to elements. What would be the right material for sealing the expansion seams in concrete? Not really interested in applying those widely advertised, cheap, "overseas" manufactured herbicides. I know some people stuff the cracks with just sand but I'm sure it'll eventually get washed out.

Also, what would be a good tool to scrape all the roots out?
Would greatly appreciate any suggestion. Best wishes, h.

Personally I'd apply a weed killer, let it work, then scrape off the dead material and respray the weed killer as needed. You'd use whatever tool fit to scrape out the roots but IMO that's more effort than it's worth.

I just use "Roundup". Kills them for quite a long bit. Respray if they start growing again. They have natural products available too, but haven't tried them.
My neighbor just hits them with a weed wacker, so guess that would work too!
I don't think there's a filler AFAIK.

Thank you all for the replies. It's surprising that long-term sealing with concrete patching caulk is not better than regular removing the weeds. I'll try just cleaning the seams and maybe filling them with sand to see how long it stays grass-free.

Instead of Roundup use a "season long" grass killer and dont worry about dirt in the cracks. Just spray it down once a year... twice if you never have frost. Roundup doesnt last long as its a contact herbicide.

Thanks! What is "a "season long" grass killer"? I scraped all the seams and cracks with a paint scraper; am reluctant to buy and spray around all these China-made herbicides. Now that the rains aren't expected until December and the sun is back sending deadly doses of UV here, I suspect that it would take the weeds some time to grow back in cleaned seams.

A) Pour boiling water on the weeds. They will die, including the roots.

B) Best tool to clean out the cracks is a power washer.

If you can rent steamer pressure washer, you combined A & B in one shot.

C) Fill the joints with lime mortar, a traditional soft, self-healing grout.
Classic formula is 2 parts lime putty to 5 parts aggregate, e.g sand.
Can also be 1 part lime, 1 part sand, 1 part stone dust.
Lime putty is lime mixed with water until it's the consistency of cream cheese.

While the lime mortar is still wet, brush/shake/dust the top of the joint
with portland cement to create a hard wearing cap on an otherwise sticky mortar joint.